Hello all
This is a summary of yesterday OGC meeting on metadata, cross-posted on
both GeoAPI and SIS lists because it will probably have a short-term
impact on those two projects. This email summarizes my understanding, I
apologize in advance if I misunderstood some points.
The current situation is:
* ISO 19115 defines the metadata model.
* ISO 19115-2 defines an extension for imagery.
* ISO 19139 defines the XML schema for ISO 19115.
* There is not yet ISO standard for 19115-2 XML schema.
Those standards are under revision. Final release of the new ISO 19115
standard is scheduled for August 2013 (current version was released in
2003). We will need to modify the GeoAPI interfaces in the
"org.opengis.metadata" package accordingly (it may be a GeoAPI 3.2
release), then reflect those changes in Apache SIS.
The new standard will actually be called "ISO 19115-1" instead than only
"ISO 19115", for consistency with the "ISO 19115-2" extension
("/Metadata extensions for imagery and gridded data/"). In GeoAPI and
Apache SIS, we may adopt the plain "ISO 19115" name as the union of the
"-1" and "-2" standards, since GeoAPI already tries to provide a unified
view of those two standards.
ISO 19115-3 will define the XML schema of ISO 19115-1 (currently defined
in ISO 19139). Likewise, ISO 19115-4 will define the XML schema of ISO
19115-2. From a Java perspective, the -1 and -2 standards define the
GeoAPI interfaces, while the -3 and -4 standards define the JAXB
annotations in the implementation of those GeoAPI interfaces. The ISO
19139 standard will continue to exist, but would contain only the rules
for creating XML schemas from the UML - so this particular standard
would not be anymore of direct use for us.
Two packages are moving: the new metadata standard will contain a new
package about services. This new package was previously defined in a
separated standard, namely ISO 19119, which is now merged with ISO
19115. On the other hand, the quality package moves to a separated
standard, namely ISO 19157. The impact on GeoAPI will be a new
"org.opengis.metadata.service" package (which currently doesn't exist),
but I propose to not move the existing "org.opengis.metadata.quality"
package for compatibility reason, and because quality information can
still be view as a kind of metadata.
There will be approximatively 100 metadata attributes added or modified.
I don't know yet how many are code lists (i.e. no work for implementors)
and how many touch interfaces. Among the changes, metadata identifiers
have been improved and CI_ResponsibleParty will be restructured for
making easier to reuse elements for different roles.
The XML schema will change, especially the prefixes. In the current
schema, the "gmd" prefix is used for every metadata elements. The new
schema takes a more modularized approach, with different prefixes for
different packages. This have no impact on GeoAPI, but will affect
implementations. XSLT will be provided for translating metadata
documents from the old schema to the new one.
Martin
